Technology related to fundamental and applied tissue engineering has been advanced for the purpose of developing transplantable artificial tissues as part of regenerative medicine. Specifically, studies including stem cell proliferation and differentiation, development of cytocompatible and biocompatible three-dimensional scaffolds, and construction of a variety of tissue engineering tools are now the most active research areas in regenerative medicine. Among them, scaffolds that are used to deliver stem cells or tissue cells therein are critical for the development of artificial tissues and organs
Scaffold materials used for the regeneration of body tissues must act as a platform to which cells adhere to form three-dimensional tissues. They must also function as a temporary barrier between transplanted cells and host cells, and they must be nontoxic and biocompatible generating tolerable immune reactions, if any are to be generated. In addition, scaffold material must be biodegradable in vivo at a desired time when the transplanted cells have grown sufficiently to the point of being able to adequately function as a tissue.
Typically, scaffolds are prepared from synthetic or natural polymers or their composites, and are manufactured into three-dimensional structures which have a variety of morphologies and properties. Most commonly used synthetic biodegradable polymers include polyglycolic acid (PGA), polylactic acid (PLA), poly(lactic acid-co-glycolic acid) (PLGA), poly-ε-caprolactone (PCL), and derivatives and copolymers thereof, which can be used as biomaterials for scaffold preparation. Naturally biodegradable polymers as exemplified by collagen, alginate, hyaluronic acid, gelatin, chitosan, fibrin, etc., are also very useful candidates for this purpose. A variety of different forms of materials, such as sponges, gels, fibers, and microbeads, are applied for the fabrication of scaffolds, and the most popular ones are porous sponges and injectable hydrogels.
Wang, M., et al (Tissue Engineering, Volume 16, Number 5, 2010) discloses a porous PLGA scaffold used for inducing the differentiation of adipose-derived stem cells (ADSCs) with a hepatic inducing medium. PLGA particles cannot significantly improve the proliferation of ADSCs in a general medium. The results indicate that ADSCs are difficult to adhesively growth on PLGA scaffolds.
Kim S E, et al (Colloids and Surfaces B: Biointerfaces 122 (2014) 457-464) discloses a porous PLGA particles with heparin-dopamine (Hep) and lactoferrin (LF) for inducing the proliferation and differentiation of cells. According to the analysis results, the cell proliferation is not significant even if the particles are modified.
Accordingly, there are many technical barriers in achieving the goal of tissue engineering perfectly. For instances, the space for cell culture is not enough, yield is too low, the amount of carried cells is too low, and success rate of cell transplantation is too low. Therefore, a functional biomaterials system is needed to be used as a cell culture scaffold and transplant carrier.